scholarly journals The Analysis of Secondary Motion and Lubrication Performance of Piston considering the Piston Skirt Profile

2018 ◽  
Vol 2018 ◽  
pp. 1-27 ◽  
Author(s):  
Yanjun Lu ◽  
Sha Li ◽  
Peng Wang ◽  
Cheng Liu ◽  
Yongfang Zhang ◽  
...  
Keyword(s):  
Thermal Deformation ◽  
Work Performance ◽  
Cylinder Liner ◽  
Connecting Rod ◽  
Piston Skirt ◽  
Piston Cylinder ◽  
Lubrication Performance ◽  
Rod System ◽  
Liner System ◽  
Secondary Motion

The work performance of piston-cylinder liner system is affected by the lubrication condition and the secondary motion of the piston. Therefore, more and more attention has been paid to the secondary motion and lubrication of the piston. In this paper, the Jakobson-Floberg-Olsson (JFO) boundary condition is employed to describe the rupture and reformation of oil film. The average Reynolds equation of skirt lubrication is solved by the finite difference method (FDM). The secondary motion of piston-connecting rod system is modeled; the trajectory of the piston is calculated by the Runge-Kutta method. By considering the inertia of the connecting rod, the influence of the longitudinal and horizontal profiles of piston skirt, the offset of the piston pin, and the thermal deformation on the secondary motion and lubrication performance is investigated. The parabolic longitudinal profile, the smaller top radial reduction and ellipticities of the middle-convex piston, and the bigger bottom radial reduction and ellipticities can effectively reduce the secondary displacement and velocity, the skirt thrust, friction, and the friction power loss. The results show that the connecting rod inertia, piston skirt profile, and thermal deformation have important influence on secondary motion and lubrication performance of the piston.

Numerical Study of Piston Skirt-Liner Lubrication Considering the Effects of Deformation in Internal Combustion Engines

2012 ◽  
Author(s):  
Lipu Ning ◽  
Xianghui Meng ◽  
Youbai Xie
Keyword(s):  
Elastic Deformation ◽  
Internal Combustion Engines ◽  
Numerical Study ◽  
Cylinder Liner ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Surface Geometry ◽  
Piston Skirt ◽  
Lubrication Performance ◽  
Liner System

This paper presents a comprehensive lubrication model for piston skirt-liner system of internal combustion engines. In the model it is included that the effects of the surface roughness, the piston skirt surface geometry, the piston pin offset, the crankshaft offset, and the lubricant viscosity on the piston secondary motion and lubrication performance. Especially, the effects of the thermal and the elastic deformation of the piston skirt and the cylinder liner, and the piston skirt deformations due to the combustion pressure and the piston axial inertia, are considered as the key task in this study. The results show that the combustion force, the working temperature and the piston axial inertia all play important roles in the piston-skirt lubrication. Also, considering the elastic deformation of the piston skirt and the cylinder liner is beneficial to the prediction of piston-skirt lubrication more accurately. The developed program in this study can provide a useful tool for the analysis of the piston-liner system lubrication problem.

Research on the lubrication performance of engine piston skirt–cylinder liner frictional pair considering lubricating oil transport

2018 ◽  
Vol 21 (4) ◽  
pp. 713-722 ◽  
Author(s):  
Jun Sun ◽  
Feifei Hao ◽  
Guangsheng Liu ◽  
Hu Wang ◽  
Qin Teng ◽  
...  
Keyword(s):  
Cylinder Liner ◽  
Lubricating Oil ◽  
Frictional Pair ◽  
Operating Cycle ◽  
Piston Skirt ◽  
Oil Transport ◽  
Bottom Dead Center ◽  
Lubrication Performance ◽  
Oil Flow ◽  
Secondary Motion

In current lubrication analysis of piston skirt, the flooded status is generally considered in the piston skirt–cylinder liner frictional pair in all strokes of an engine operating cycle. However, the quantity of lubricating oil at the entrance of piston skirt cannot always ensure the sufficient lubrication status of piston skirt–cylinder liner frictional pair when the piston moves from the bottom dead center to the top dead center in actual engine. In this article, based on the model of piston secondary motion, fluid lubrication, and lubricating oil flow, the lubrication performance of piston skirt–cylinder liner frictional pair is analyzed, in which the quantity of lubricating oil detained on the surface of cylinder liner after the piston skirt moves from the top dead center to the bottom dead center and is considered as the quantity of lubricating oil at entrance of piston skirt when the piston moves from the bottom dead center to the top dead center. The results show that compared with current analysis, in which the sufficient lubrication of piston skirt–cylinder liner frictional pair is assumed in all strokes of engine, there are remarkable changes for the lubrication performance of piston skirt–cylinder liner frictional pair and the piston secondary motion when the lubrication status of the frictional pair in the upstroke of piston is determined by considering actual lubricating oil transport in the lubrication analysis of piston skirt.

Mutual influence of plateau roughness and groove texture of honed surface on frictional performance of piston ring–liner system

2016 ◽  
Vol 231 (7) ◽  
pp. 838-859 ◽  
Author(s):  
Yang Hu ◽  
Xianghui Meng ◽  
Youbai Xie ◽  
Jiazheng Fan
Keyword(s):  
Piston Ring ◽  
Cylinder Liner ◽  
Texture Features ◽  
Groove Depth ◽  
Mixed Lubrication ◽  
Operating Conditions ◽  
Friction Reduction ◽  
Lubrication Performance ◽  
Liner System ◽  
Frictional Performance

The cylinder liner surface finish, which is commonly produced using the honing technique, is an essential factor of engine performance. The characteristics of the texture features, including the cross-hatch angle, the plateau roughness and the groove depth, significantly affect the performance of the ring pack–cylinder liner system. However, due to the influence of the honed texture features, the surface roughness of the liner is not subject to Gaussian distribution. To simulate the mixed lubrication performance of the ring–liner system with non-Gaussian roughness, the combination of a two-scale homogenization technique and a deterministic asperities contact method is adopted. In this study, a one-dimensional homogenized mixed lubrication model is established to study the influence of groove parameters on the load-carrying capacity and the frictional performance of the piston ring–liner system. The ring profile, plateau roughness, and operating conditions are taken into consideration. The main findings are that for nonflat ring, shallow and wide groove textures are beneficial for friction reduction, and there exists an optimum groove density that makes the friction minimum; for flat ring, wide and sparse grooves help improving the tribological performance, and there exists an optimum groove depth that makes the friction minimum.

Effect of piston clearance on the lubrication performance in axial piston pump

2019 ◽  
Vol 72 (1) ◽  
pp. 146-150
Author(s):  
Bora Lee ◽  
Yonghun Yu ◽  
Yong-Joo Cho
Keyword(s):  
Reynolds Equation ◽  
Design Method ◽  
Contact Region ◽  
Content Type ◽  
Piston Cylinder ◽  
Leakage Flow Rate ◽  
Lubrication Performance ◽  
Secondary Motion ◽  
Lubrication Characteristics ◽  
Axial Piston

Purpose This paper aims to provide a reliable and efficient numerical piston–cylinder design method and assess the effect of clearance on the piston-cylinder lubrication. Design/methodology/approach Numerical analyses of lubrication characteristics were performed for the piston–cylinder interface. The axial piston was numerically modeled, and the film pressure was calculated using the unsteady two-dimensional Reynolds equation. The behavior of the piston was analyzed by calculating the eccentricity satisfying the force and moment balance. Findings The secondary motion of the piston included numerically simulated several cycles until the piston behavior converged, and contact with the inner wall of the cylinder and friction region was estimated. Results showed that the piston–cylinder clearance affected the contact force, length of the contact region and leakage flow rate. Originality/value This result improves the understanding of the piston–cylinder lubrication and suggests considerations in terms of lubrication in clearance design.

Numerical Study of Piston Skirt-Liner Elastohydrodynamic Lubrication and Contact by the Multigrid Method

2010 ◽  
Author(s):  
Xianghui Meng ◽  
Youbai Xie
Keyword(s):  
Contact Problem ◽  
Internal Combustion Engines ◽  
Multigrid Method ◽  
Numerical Study ◽  
Elastohydrodynamic Lubrication ◽  
Cylinder Liner ◽  
Piston Skirt ◽  
Liner System ◽  
Tribological Analysis ◽  
Quasi Newton

The cylinder liner-piston system of internal combustion engines is one of the key friction pairs running at the most rigor working conditions. Under the influence of elastohydrodynamic lubrication and contact between the piston skirt and the liner, the dynamic process of piston is a nonlinear and stiff problem difficult to be analyzed accurately and easily. To reach a stable and rapid convergence in analysis, the MEBDF method and the multigrid method are used to solve the piston-skirt elastohydrodynamic lubrication and contact problem. Firstly the solving process of the piston dynamics is analyzed based on the MEBDF method. Then the residual equations for the elastohydrodynamic lubrication pressure are built based on the multigrid method. And the solving method of the nonlinear residual equations is presented based on the quasi Newton-Raphson method. Finally the numerical simulation program is developed based on the MEBDF method and the multigrid method. The elastohydrodynamic lubrication and contact problem of the piston skirt-liner system is simply analyzed based on the simulation. The study in this paper can provide an effective method for tribological analysis and optimization of piston–liner system in the future.

scholarly journals Study of the Piston Secondary Movement on the Tribological Performance of a Single Cylinder Low-Displacement Diesel Engine

Lubricants ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 97
Author(s):  
Jorge Duarte Forero ◽  
Guillermo Valencia Ochoa ◽  
Wlamyr Palacios Alvarado
Keyword(s):  
Mathematical Model ◽  
Diesel Engine ◽  
Hydrodynamic Lubrication ◽  
Lateral Displacement ◽  
Cylinder Liner ◽  
Deformation Model ◽  
Analysis Tool ◽  
Connecting Rod ◽  
Single Cylinder ◽  
Piston Skirt

The present study aims to analyze the secondary movement of the piston considering the deformations present in the piston skirt, the hydrodynamic lubrication, and the effects of the clearances in the connecting rod bearings. The analysis of the piston movement is performed by developing a mathematical model, which was used to evaluate the dynamic characteristics of the piston movement, the slap force on the piston skirt, the effect of the secondary piston movement on the connecting rod, and the influence of clearances in the connecting rod bearings and in the piston. For the study, the geometric of the crankshaft-connecting rod–piston system of a single-cylinder diesel engine is taken as a reference. The deformation model of the piston was carried out by means of a symmetric finite element model (FEM), which was integrated into the mathematical model of the piston. MATLAB® software (The MathWorks Inc., Natick, MA, USA) is used for the development of model simulations. The obtained results show that during the combustion cycle, there are six changes of direction in the secondary movement of the piston with lateral and angular velocities that can reach a magnitude of 0.13 m/s and 4 rad/s. The lateral and angular movement of the piston during its travel causes the appearance of impacts on the piston skirt with the cylinder liner, which produces an increase of approximately 500 N in the hydrodynamic forces in the connecting rod bearings. The force analysis shows that the range of the maximum magnitudes of these forces is between 1900 N and 3480 N. The increase in clearance between the cylinder liner and the piston skirt (Cpc) causes a greater lateral displacement and an increase in the angle of inclination of the piston. Analysis of the change in connecting rod bearing clearance shows that there are critical values in relation to clearance Cpc. The model presented allows us to analyze the different characteristics of the secondary movement of the piston, which involve the interaction between the piston skirt and the cylinder liner. Additionally, the influence of this movement on the connecting rod bearings is considered. The foregoing can be used as an analysis tool for the study of designs and/or modifications in the engine in such a way that greater durability of the components, reductions in acoustic emissions, and reduction in friction losses are achieved.

Effect of axial piston pin motion on tribo-dynamics of piston skirt-cylinder liner system

2018 ◽  
Vol 70 (1) ◽  
pp. 140-154
Author(s):  
Fanming Meng ◽  
Minggang Du ◽  
Xianfu Wang ◽  
Yuanpei Chen ◽  
Qing Zhang
Keyword(s):  
Internal Combustion Engine ◽  
Combustion Engine ◽  
Cylinder Liner ◽  
Internal Combustion ◽  
Axial Motion ◽  
Content Type ◽  
Piston Skirt ◽  
Operation Conditions ◽  
Liner System ◽  
Axial Piston

Purpose The purpose of this study is to investigate the effects of the axial piston pin motion on the tribological performances of the piston skirt and cylinder liner vibration for an internal combustion engine (ICE) under different operation conditions. Design/methodology/approach The dynamic equation for the piston incorporating into axial piston pin motion is derived first. Then, the proposed equation and associated lubrication equations are solved using the Broyden algorithm and difference method, respectively. Moreover, the axial motion of the piston pin and its slap on the cylinder liner are studied under different operation conditions. Findings The axial piston pin motion leads to an overall increase in the friction power consumption. Increments in the ICE speed and lubricant viscosity can augment the axial pin motion and cylinder liner vibration, especially in the power stroke. The said increments cause the instability of the piston motion in the cylinder. The axial motion of piston pin can be restrained through the eccentricity of the piston pin close to the thrust side of the cylinder liner. Originality/value This study conducts detailed discussions of the effect of axial piston pin motion on tribological and dynamic performances for piston skirt-cylinder liner system of an internal combustion engine and gives a helpful reference to analyses and designs of internal combustion engines.

scholarly journals Numerical study on the lubrication performance of compression ring-cylinder liner system with spherical dimples

PLoS ONE ◽  
2017 ◽  
Vol 12 (7) ◽  
pp. e0181574 ◽  
Author(s):  
Cheng Liu ◽  
Yan-Jun Lu ◽  
Yong-Fang Zhang ◽  
Sha Li ◽  
Norbert Müller
Keyword(s):  
Numerical Study ◽  
Cylinder Liner ◽  
Compression Ring ◽  
Lubrication Performance ◽  
Liner System

Impact of the Piston Secondary Motion on its Slap Force

2014 ◽  
Vol 553 ◽  
pp. 582-587
Author(s):  
Bao Cheng Zhang ◽  
Tong Li ◽  
Hai Fei Zhan ◽  
Yuan Tong Gu
Keyword(s):  
Theoretical Model ◽  
Boundary Conditions ◽  
Internal Combustion Engine ◽  
Combustion Engine ◽  
Cylinder Liner ◽  
Internal Combustion ◽  
Lubricating Oil ◽  
Actual Condition ◽  
Piston Skirt ◽  
Secondary Motion

A theoretical model is developed for the analysis of piston secondary motion. Based on this model, the slap force of a specific L6 diesel engine was compared when considering different boundary conditions, such as lubricating oil on cylinder liner, surface roughness, deformation of cylinder liner and piston skirt. It is concluded that it is necessary to consider the secondary motion of piston in the analysis of the inner excitation for an internal combustion engine. A more comprehensive consideration of the boundary condition (i.e., more close to the actual condition) will lead to a smaller maximum slap force, and among all boundary conditions considered in this paper, the structural deformation of the piston skirt and cylinder liner is the most influential factor. The theoretical model developed and findings obtained in this study will benefit the future analysis and design of advanced internal combustion engine structures.

scholarly journals Research on the influence of key structural parameters on piston secondary motion

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Haixiang Yang ◽  
Jilin Lei ◽  
Xiwen Deng ◽  
Jun Wen ◽  
Zhigao Wen ◽  
...  
Keyword(s):  
Power Loss ◽  
Structural Parameters ◽  
Cylinder Liner ◽  
Oil Consumption ◽  
Frictional Loss ◽  
Significance Level ◽  
Friction Power ◽  
Piston Skirt ◽  
Secondary Motion ◽  
Response Method

AbstractPiston secondary motion not only influences the side knocking of piston and frictional loss, but also influence the in-cylinder oil consumption and gas blow-by. An inline four-cylinder common rail diesel engine was chosen as the research object. Dynamic simulation model of piston assembly was built based on the piston and cylinder liner temperature field test. The impacts of pinhole offset, liner clearance and piston skirt ovality on piston secondary motion were researched. Based on the surface response method, the influence of multiple factors on friction power loss and slapping energy is estimated. The results indicate that: in-cylinder stress condition of piston will change with its structural parameters, then the secondary motion of piston will be affected as a result. Pinhole offset, liner clearance, piston skirt ovality and the interaction of the latter two all have significant effects on the friction power loss, while the slapping energy is significantly affected by liner clearance. Therefore, the parameters can be designed based on the significance level to optimize the secondary motion characteristics of the piston.

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